PostCSS Media Legacy
PostCSS plugin for Mobile First development that rewrites media queries for IE8 and below.
Use this plugin with Modernizr or adding the class "lt-ie9" in your html element.
npm install postcss-media-legacy --save
Plug it in to PostCSS
Plug it in just like any other PostCSS plugin. There are no options at the moment.
Or take advantage of any of the myriad other ways to consume PostCSS, and follow the plugin instructions they provide.
It doesn't require any dependencies, but it has to be loaded after postcss-nested if included.